乙醛电合成乙二醛的研究

采用电化学方法用乙醛合成了乙二醛。以DSA(dimensionally stable anodes)电极作阳极,铅电极做阴极,阳离子交换膜作电解液隔离膜,亚硝酸钠和氯化镁溶于乙醛水溶液配制的混合溶液作阳极电解液,盐酸溶液作阴极电解液。在电解电压为2.5 V,电解时间为3 h,超声波频率为40 kHz、功率为60 W,电解温度为25℃的条件下电解乙醛生成乙二醛,最大产率为14.4%。     

无接触电解抛光

本文介绍的无接触电解抛光方法是以让阳极和阴极面向工件,而工件并没有与电源相连接的方式进行电解抛光的方法。文中列举了这种电抛光效率的数据,并指出面向阴极的表面之抛光效率取决于电解液的导电率和电极的位置。这种方法应用于连续性的带材和线材的电解抛光相当有效。     

电解二氧化锰制造过程中,除去阴极外皮的方法

发明的详细说明本发明系以硫酸、硫酸锰水溶液为电解液,用不溶性电极制造电解二氧化锰时,除去在电解过程中阴极表面产生的外皮方法。在电解二氧化锰制造过程中,电极用不溶于电解液的材料。通常以铅、铅合金、石墨电极为阴极,以铅合金、碳精棒、钛电极为阳极。电解二氧化锰的电解条件:例如阳极电流密度为0.6～1.2安/分米~2,电解液温度为85～95℃,电解液浓度为Mnll～55克/升、H_2SO_420～100克/升。阳极每10～35天取出,用适当的方法,如轻轻敲打,把电解     

应用离子交换膜通过电化学氧化合成氯甲苯

以钛网为阳极,镍网为阴极,饱和的NaCl溶液为阳极电解质,应用离子交换膜通过阳极氧化甲苯的方法合成氯甲苯。讨论了阳极电解质质量分数、电流密度、电解液温度、反应时间等反应条件的选择。结果表明：在反应温度25 ℃,阳极、阴极电解液分别为25％NaCl和10％NaOH溶液,电流密度为10～15 A/dm2条件下电解,并在4.5 h左右结束反应,氯甲苯的产率最高,可达55.5％,电流效率为51.5％。     

阴极冷却固定床反应器电合成乙醛酸

以过饱和草酸水溶液为阴极液,盐酸溶液为阳极液,在阴极冷却固定床电化学反应器内草酸电解合成乙醛酸。考察了电流密度、电极和电解液温度、阴极材料对合成乙醛酸时空产率和电流效率的影响。结果表明,阴极冷却固定床反应器是一种较理想的反应器,用石墨板作阳极,铅作阴极,电流密度为400.5A/m2,阴极空速u0=0.505m/s,电解温度为20℃左右时,电解1.5h,在阴极可得到质量分数为5.45%的乙醛酸溶液,平均时空产率可达0.12kg/dm3·h以上。     

M电化学方法制备碘化氢(续)

正(上接第5期第42页)半连续或连续方式操作。阳极电解室(46)装有阳极电极(48)和阳极电解液(50),典型的氧化剂水溶液,比如碘酸,其可以氧化任何对面迁移过来的碘离子,形成可溶性碘化物,同时还作为载流电解质。阴极电解室(52)装有阴极电极(54)以及含有碘的阴极电解液(56),例如三碘化物在阴极电解室还原成碘离子。     

电合成对氟苯甲醛的研究

以PbO2 /Ti为阳极 ,Pb为阴极 ,于无隔膜电解槽中将Mn(Ⅱ )电氧化成Mn(Ⅲ ) ,产率为87 0 % ,电流效率为 71 5 % ,明显优于用Pb(+) -Pb(- )电极对的电解结果。电解液可循环使用。以Mn(Ⅲ )为氧化媒质 ,采用槽外式间接电合成法将对氟甲苯氧化成对氟苯甲醛 ,产率为76 5 %。     

专利信息 吡啶系列化合物

3,6-二氯吡啶甲酸的电解合成方法及设备以3,4,5,6-四氯吡啶甲酸为主要电解原料,电解液置于电解槽中电解,反应结束后中和、冷却结晶、过滤、干燥即得3,6-二氯吡啶甲酸,其中通过稳压稳流可控硅周期换向电源自动对电解槽的阴极进行粗糙化处理。所述的电解合成设备包括电源、配料槽、电解槽,所述的电源为稳压稳流可控硅周期换向电源,电源连接电流换向器,电流换向器设有程序控制单元;电源的正极连接电解槽阳极,电源的负极连接电解槽阴极。所述的电解合成设备,解决了目前电解合成过程中的诸多缺陷,具有较大的实用价值和社会经济效益。公告号:CN100436648C申请人:浙江工业大学     

碳氟表面活性剂合成与应用研究

系统归纳了碳氟表面活性剂主要合成方法——电解氟化法、调聚法和齐聚法,对比分析了各种合成方法的优缺点及用于合成碳氟表面活性剂的重要中间体,探讨了其分子结构对生态环境的影响及其发展趋势,具有低生物积累性和低生物毒性的短链碳氟表面活性剂将是未来研究重点。阐述了碳氟表面活性剂在石油、消防等领域的应用现状。根据表面活性剂清洗含油钻屑的作用原理,提出了利用碳氟表面活性剂改变钻屑表面润湿性来清洗细粒含油钻屑的新思路。     

阳极磁增强对电解制氢速率的影响

本文主要在电解产氢装置上加持磁性用于探究电解产氢速率.在碱性电解液中,于阳极上加持不同磁场强度,观察并记录电解制氢的速率,探究电解制氢原理及制氢影响因素等.实验利用(自制霍夫曼电解器)以铁电极为阴极,以磁性金属镍为阳极,电磁铁提供磁场,通过改变电磁铁中电流大小来对磁场强度进行调控,以此来找到最佳磁场强度,探究电磁铁电压...     

三价铬电镀工艺初步研究

本文以甲酸-尿素体系三价铬镀铬液为基础液,石墨电极为阳极条件下,以钢片或铜片为阴极,探讨了不同润湿剂和用量,不同酸度对三价铬电镀效果的影响,得到较好的三价铬。镀铬条件是:石墨电极作阳极,铜片作阴极,OP乳化剂作润湿剂,pH=0.5,可得到光泽度较好,有一定厚度的铬镀层。     

Electrolytic preparation of magnesium perchlorate

The electrochemical preparation of magnesium perchlorate from magnesium chlorate employing a platinum anode and a rotating stainless steel cathode is described. The effect of electrolyte concentration, cathode and anode current densities, pH and temperature of the electrolyte and cathode rotation on current efficiency for the preparation of magnesium perchlorate was studied. A maximum current efficiency of 65–72% was achieved. Based on the results obtained on the laboratory scale, a 100 A cell was designed, fabricated and operated.     

An experimental study on the placement of reference electrodes in alkaline polymer electrolyte membrane fuel cells

The ability to accurately measure separate in situ anode and cathode overpotentials and impedance responses is still a source of debate when investigating fuel cells of planar configuration containing <100 μm thickness solid electrolytes and when using the common three-electrode arrangement. The results obtained in this study indicate that the overpotentials and impedances of the anode and cathode can be successfully measured when using two spatially separated reference electrodes and when the cathode and anode of alkaline membrane electrode assemblies (for alkaline polymer electrolyte membrane fuel cells) are precisely and optimally misaligned. The frequency dependent response between the two reference electrodes is attributed to the membrane response and the “crosstalk” between anode and cathode.     

表面活性剂对复合刷镀液中纳米WC分散性的影响

研究了在(Ni-P)-纳米WC复合刷镀液中添加阴离子型表面活性剂SDS、阳离子型表面活性剂PEI、非离子型表面活性剂OP对分散体系分散效果的影响.结果表明:表面活性剂能有效阻止复合刷镀液中微粒的絮凝、团聚,其用量对复合刷镀液分散效果有显著的影响.当阴离子型表面活性剂SDS的质量浓度为0.2g/L,阳离子型表面活性剂PEI为O.8g/L时,刷镀液中沉降粉体体积最小,添加非离子型表面活性剂OP的分散体系分散效果较差.     

物理成孔剂水洗工艺的改进

将表面活性剂引入到硅橡胶泡沫成孔剂的水洗工艺中,结果表明,加入非离子表面活性剂能有效提高尿成孔剂的水洗速率,当非离子表面活性剂OP-10的质量分数为0.3%,水洗温度为60℃,换水频率为1/3 h-1,样品与OP-10水溶液的质量比为1∶10时,水洗56 h后,成孔剂基本上全部溶出。     

Effect of water transport properties on a PEM fuel cell operating with dry hydrogen

In this work, membrane resistance measurement and water balance experiment were implemented to investigate the feasibility for a PEM fuel cell operating with dry hydrogen. The results showed that when a thin membrane was used in a cell the performance and the membrane resistance changed a little while the anode humidity changed from saturated to dry. Comparing with the anode humidity, the influence of the cathode humidity was serious on the cell performance. The water balance experiments showed that the net water transport coefficient was negative even the anode was humidified and liquid water existed not only in the cathode but also in the anode. High cathode humidity was disadvantage for the removal of water both in the anode and the cathode.     

Effect of Ionomer Content in Anode and Cathode Catalyst Layers on Direct Methanol Fuel Cell Performance

The influence of ionomer content on the performance of direct methanol fuel cells (DMFC) is studied. The performance is studied as a function of the (nafion/carbon, N/C) ratio on the anode and cathode. The performance of the DMFC has been found to increase as a function of the N/C ratio. The ionomer content seems to influence the catalyst layer resistance in the anode and cathode and also the methanol oxidation potential on the anode. On the cathode, catalyst utilisation is seen to be affected by the ionomer content. Cyclic voltammetry (CV) is used to study the effect of ionomer content on Platinum (Pt) utilisation on the cathode. Theoretical calculations are used to study the catalyst layer resistance on the anode and cathode as a function of ionomer content. Findings indicate that ionomer content plays only a partial role in characterising the performance of a DMFC.     

Microemulsion Systems with Rhodium Tris(3-sulfophenyl)phosphine Trisodium Salt Complex for Product Isolation and Catalyst Recycling in the Hydrogenation of Dimethyl Itaconate

Microemulsion systems with the nonionic surfactant p-tert-octylphenoxy polyethoxyethanol (OP9.5EO), the anionic surfactant dioctyl sulfosuccinate sodium salt (DOSS) and the narrow range nonionic surfactant alkyl polyethylene glycol ether (C10EO5) were used as solvent systems in the catalytic hydrogenation of dimethyl itaconate (DMI) catalysed by the water soluble catalyst complex Rh-TPPTS in order to achieve product isolation and catalyst recycling. The DOSS systems, which are more sensitive to the substrate and catalyst addition allowed for the hydrogenation to proceed with an initial hydrogenation rate about three times higher than with the nonionic surfactants, when the surfactant concentration was 15 wt%. Systems with 3 wt% surfactant were used in order to accomplish catalyst recycling. With a biphasic DOSS mixture a turnover number (TON) of 1,200 mol of DMI hydrogenated per mol of catalyst (Rh) was obtained in 3 consecutive runs. A three-phase system for the OP9.5EO mixture allowed the catalyst to be recycled 3 times and a TON of 1,500 in 4 runs was obtained. A TON of 800 in 2 runs was obtained using a three-phase C10EO5 mixture.     

Effect of anode and cathode flow field depths on the performance of liquid feed direct methanol fuel cells (DMFCs)

The effect of the anode and cathode flow field depths on the performance of a single cell Direct methanol fuel cell (DMFC) of 45 cm² active area were experimentally investigated. Double serpentine flow fields (DSFFs) with varying channel depth namely, 0.2, 0.4, 0.6, 0.8, and 1 mm but with fixed channel and rib width each of 1 mm on both anode and cathode were designed, fabricated, and tested. The experimental study involved measurement of pressure drops across anode and cathode flow field plates, polarization, and carbon dioxide concentration measurements at various current densities. The mass transport at both anode and cathode were found to increase with increase in pressure drop across the flow field on account of reduced channel depth from 1.0 to 0.4 mm at all current densities. However, further decrease to a channel depth of 0.2 mm was found to be counter-productive with different phenomena operating on either side viz., increased CO₂ slug length on the anode flow channel and increased methanol crossover on the cathode side. Hence, the maximum performance for DMFCs was observed for a channel depth of 0.4 mm on anode and cathode flow fields. A decrease in flow field channel depth at cathode was found to increase the methanol crossover due to convective mass transfer effect.     

表面活性剂在HCl中对钢的缓蚀协同效应

用失重法和电化学法研究了在1.0 mol/L HCl中阴离子表面活性剂油酸钠(SO)和非离子表面活性剂聚乙二醇辛基苯基醚(OP)对冷轧钢的缓蚀协同作用.研究结果表明,单独的SO和OP对冷轧钢具有一定的缓蚀作用,为混合型缓蚀剂,且在钢表面的吸附符合Temkin吸附模型.当两者复配后产生了明显的缓蚀协同效应,最大缓蚀率可达92%.